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Here we have a little set-up
to illustrate a light sensor,
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in fact, quite a
few light sensors.
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You can see an array of lights,
and associated with each
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is a sensor.
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And at the moment,
all of these are
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illuminated by light
coming from the outside.
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But if I were to
cover some of them,
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then a light sensor detects
that and will turn it
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on the associated LED.
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So if I do that, you can see.
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Again, sweep the
other way-- depending
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on which of the lights
lose the brightness,
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the sensors then the
appropriate lights turn on.
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Here, more or less,
just down one side.
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Here just about only
covering this side.
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So a nice little demonstration
of what light senors can do.
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We can use those, and we do,
in fact, use those on the ERIC.
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Here we have the ERIC
using its light sensor,
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and when it starts to see
the light is going down,
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it turns away, so it
goes back towards where
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the light is the brightest.
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Going to turn the
lights off to see what
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happens, whether it will
move from its current region
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to the other one.
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It's now detected the new area,
so ERIC has successfully moved
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from one region to the other.
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